WO2017129213A1

WO2017129213A1 - Screwing machine

Info

Publication number: WO2017129213A1
Application number: PCT/EP2016/002170
Authority: WO
Inventors: Otto Widlroither; Dieter Kamml
Original assignee: Robel Bahnbaumaschinen Gmbh
Priority date: 2016-01-29
Filing date: 2016-12-22
Publication date: 2017-08-03
Also published as: AU2016389115B2; CN108603347B; CN108603347A; RU2018121513A; EP3408451A1; DE102016000968A1; RU2734663C2; JP2019507259A; BR112018015087A2; US20190003131A1; PL3408451T3; RU2018121513A3; BR112018015087B1; US10934666B2; EP3408451B1; AU2016389115A1

Abstract

The invention relates to a screwing machine (1) for tightening or releasing rail fixing screws (9), comprising a machine frame (5) which can be rolled on a track (3), handles (8) for moving the screwing machine, a motor (7) for applying a torque (16) to a screw head (11), and a device for transmitting a torque. A measuring device (17) is provided opposite the machine frame (5) in order to detect a reaction torque (21) of the motor (7). The motor (7) is actuated in order to limit the torque (16) depending on the reaction torque (21). The reaction torque (21) is used as a reference variable, said reaction torque being applied to the machine frame (5) by the motor (7) and being ascertainable with a high degree of precision by means of a simple measuring device (17). In this manner, a simple and robust design and a precise rotational speed limiting function are implemented.

Description

description

Wrench field of engineering

The invention relates to a screwdriver for tightening or loosening of

Rail fastening screws with a machine frame which can be rolled up on a track, with handles for displacement and with a motor for acting on a screw head with a torque and with a device for limiting the torque. In addition, the invention relates to a method for operating the screwdriver.

State of the art

From DE 10 2010 023 798 A1 discloses a screwing machine is known, the

Applying a limited torque comprises a servo wrench. A processor equipped with a data memory is one

Rotary angle and connected to a torque sensor to specify a desired torque with which a screw is to be tightened.

[03] In such a servo wrench, a torque measuring shaft is integrated directly into a spindle of the screwdriver. This requires a complex storage and extends the spindle, which makes the design of the screwing complicated. In addition, a servo-driver is sensitive to mechanical damage.

[04] WO 2006/058552 A1 discloses a mechanical screwing machine, in which by means of an electromagnetically switchable friction clutch

Torque limitation is adjustable. Due to the wear and the inertia of the mechanical components it comes to it

Inaccuracies that are not negligible.

[05] A screwdriver with an alternative drive system is out of the

DE 44 14 886 A1. In addition to a mechanical drive, a hydraulic drive is provided to a pre-screwed

Tighten screw connection with a specified torque. In this case, a hydraulic pressure as a reference for a tightening torque

relied on. Inaccuracies hereby are due to the existing ones

Temperature and viscosity dependence conditionally.

Summary of the invention

[06] The invention is based on the object of specifying an improvement over the prior art for a screwing machine of the type mentioned in the introduction. In particular, a simple structure and high accuracy are intended. In addition, a corresponding procedure should be set out.

[07] According to the invention this object is achieved by a screwing machine according to independent claim 1 and a method according to independent claim 12. Dependent claims indicate advantageous embodiments of the invention.

Specifically, a measuring device for detecting a reaction torque of the motor is arranged relative to the machine frame, wherein the motor is controlled to limit the torque as a function of the reaction torque. The reference moment becomes the reaction moment

used, which acts from the engine on the machine frame and can be determined by a simple measuring device with high accuracy. On the one hand a simple and robust construction and on the other hand a precise speed limitation are realized.

[09] In an advantageous embodiment of the invention, the

Measuring device, a force transducer for measuring a force acting on the engine force. Here, the reaction torque is not measured directly, but a force that exerts the machine frame on the engine. The force prevents movement of the engine relative to the

Machine frame. There is a proportional relationship between the force and the reaction torque that is uniquely determined by the geometry of an existing engine mount.

[10] Conveniently, the engine is a hydraulic motor or an electric motor.

whereby a high torque is available with a small size.

In addition, a hydraulic motor is due to its robust and low-maintenance design very well suited for the demanding conditions on track construction sites. An electric motor is also easy to control and allows the operation of the screwdriver means

Accumulator as an electric machine or as a hybrid machine. These advantages are combined according to the present invention with a very accurate torque limiting.

A simple advantageous construction of the screw is characterized

in that a control is provided, which is a for

Reaction torque is supplied proportional value and that the

Control is set up to control the motor depending on the measured value.

Furthermore, it is advantageous if the screw head rotationally against a

Drive shaft of the motor is connected. Between these two

Components are provided without transmission equipment such as clutches or gears, creating a direct and lossless

Torque transmission between the motor and screw head is ensured. The absence of damping or elastic transmission means causes the attachable by means of the screw head to a screw

Torque with high accuracy from the reaction torque of the engine is derivable.

In an advantageous embodiment, the motor is rotatably mounted on the machine frame about a predetermined axis. By means of this predetermined axis, the resulting reaction torque is easily determinable.

It is advantageous if the motor is rotatably mounted about a shaft axis of the motor. In this way, the motor and the screw head are rotatably mounted about the same axis. The motor is supported against rotation, wherein a support torque or a support force for detecting the reaction torque is measured. No leverage effects have to be taken into account and the determined reaction torque corresponds exactly to the torque which can be applied by means of the screw head with the opposite sign.

Conveniently, the engine is mounted by means of a rolling bearing on the machine frame. This friction losses are excluded, which in the Determination of the torque to be limited should be considered.

A structurally simple design provides that the engine over the

Machine frame is supported by a torque arm and that the measuring device for detecting a means of torque arm

applied support force is formed. In the torque arm affects the entire support force, which blocks a rotational movement of the motor relative to the machine frame. In this way, a single sensor is sufficient to detect the reaction torque.

For a compact design of the screwdriver, it is advantageous if the

Measuring device is integrated in the torque arm. In addition, acts in a rod-shaped torque arm whose ends are hinged, a pure tensile or compressive force that is very accurate measurable even with a simple load cell.

An alternative embodiment provides that the engine at a

Receiving device of the machine frame is attached and that the measuring device is integrated in particular in the receiving device. In a movably mounted motor, this is supported at least at an attachment point, wherein the measuring device in the

Attachment point acting force measures. It may also be advantageous to provide a fixed attachment of the engine and to carry out force measurements by means of the measuring device at an attachment point or at a plurality of fastening points in order to detect the reaction torque of the motor.

In the method according to the invention, the screw head is acted upon by the motor with the torque, wherein by means of the measuring device, the reaction torque of the motor relative to the machine frame is detected and wherein the motor is controlled to limit the torque as a function of the reaction torque. The torque acting on the screw head is easily adjustable in this way, wherein the detected reaction torque is used as a characteristic for the torque actually occurring.

[20] It is advantageous if, for detecting the reaction torque by means of a force transducer, a measured value for a force acting on the engine is measured when the measured value is fed to a controller and when the controller controls the motor as a function of the measured value. A single measured value is used to determine the reaction moment. In this way, the control can be executed with simple components and requires no complex arithmetic operations.

[21] In a simple further development of the method, the controller enters

adjustable limit value, whereby the motor is deactivated as soon as the measured value reaches the limit value. It will not be the controller

Predetermined torque value, but for example a maximum value for a force measured by means of measuring device, wherein there is a known relationship between force and torque.

Furthermore, it is advantageous if the controller is a hydraulic

Pressure limiting valve specifies a limiting value, if a

Hydraulic motor to reach the limit value runs when the detected when stopping the hydraulic motor reaction torque is compared with a desired torque and when dependent on this comparison, the controller specifies an adjusted limit value. The hydraulic motor is driven iteratively in response to the reaction torque. During a tightening operation of a rail fastening screw, the torque actually applied is determined on the basis of the reaction torque. If it deviates from a setpoint due to a temperature or viscosity change, the controller adjusts the limit value for the next tightening procedure accordingly. In this way, the otherwise in a control loop disturbing response delay when stopping a hydraulic motor is negligible.

Brief description of the drawings

[23] The invention will now be described by way of example with reference to the accompanying drawings. It show in more schematic

Presentation:

[24] Fig. 1 screwing machine on a track

[25] Fig. 2 Detail A of the screwing machine in an oblique view

[26] Fig. 3 Detail A of the screwing machine in plan view Description of the embodiments

A screwing machine 1 shown in FIG. 1 has a machine frame 5 which can be moved by means of rollers 2 on a rail 3 of a track 4. At this a hydraulic unit 6 for generating hydraulic pressure for supplying a motor 7 is fixed. In addition, with the

Machine frame 5 handles 8 connected to move the screwdriver 1. For tightening and loosening a rail fastening screw 9, a screw head 11 which can be set in rotation by a drive shaft 10 is provided.

[28] The hydraulic unit 6 comprises an internal combustion engine 12 and a

Hydraulic pump 13 and is shielded by a panel 14 to an operator to limit the noise. Via hydraulic lines, not shown, designed as a hydraulic motor motor 7 is connected to the hydraulic unit 6.

In the area of the handles 8, a controller 15 is arranged, with

Controls and displays for adjusting an applied torque 16. The controller 15 is connected via lines not shown to the motor 7 and with control valves of the motor 7. In addition, connecting lines to the hydraulic unit 12 and to a

Measuring device 17 is provided. The latter is integrated in the exemplary embodiment in a torque arm 18.

[30] With reference to FIGS. 2 and 3, the operation of the measuring device 17 will be explained in more detail. The motor 7 is rotatably supported by a rolling bearing 19 relative to the machine frame 5 about a shaft axis 20. As soon as the screw head 11 is subjected to the torque 16 by means of the motor 7, a reaction moment 21 acts on the machine frame 5. Specifically, this is a torsional moment that occurs at both ends of the transmission line between the motor 7 and the screw head 11.

[31] The reaction torque 21 is detected by means of the measuring device 17, which comprises, for example, a force transducer which is designed as a component of the rod-shaped torque support 18. Due to the support of the motor 7 by means of the torque arm 18 acts in the Torque support 18 a supporting force 22 in the longitudinal direction. A multiplication of this supporting force 22 with a Hebelarmdistanz 23 corresponds to

Reaction torque 21. About this relationship, the torque 21 is limited in a simple and accurate manner.

Specifically, the control of the designed as a hydraulic motor takes place

Motors 7 in such a way that the controller 15 a hydraulic

Pressure limiting valve specifies a limiting value. Thus, the hydraulic pressure is limited to a value that causes the applied torque 16 according to the specification of the hydraulic motor. As soon as the maximum pressure is reached during a tightening operation and the hydraulic motor stops, the reaction moment 21 detected thereby is used to adjust the limiting value. For example, if the derived from the detected reaction torque 21 torque 16 is too low, the pressure limiting valve for the next tightening a higher limit value is specified.

[33] Also included in the invention are various other embodiments.

For example, instead of a hydraulic motor, an electric motor may be provided with a corresponding electrical supply. Instead of a hydraulic unit 6, a generator set is then arranged on the machine frame 5. The good controllability of the electric motor allows a simplified motor control, wherein the measured by means of the measuring device 17 measured value of the controller 15 is supplied and continuously compared with a limit value. In this case, the limit corresponds to the predetermined torque 16, with which the rail fastening screw 9 is to be tightened.

[34] The limit is stepless or with a given scaling

adjustable to adapt the screwdriver 1 to the given requirements. In addition, it may be useful to constantly compare the measured value with a threshold which is lower than the predetermined limit value. Upon reaching this threshold, the controller 15 reduces the speed of the motor 7 to hide 16 dynamic effects when applying the maximum torque. In an embodiment, not shown, the motor 7 is fixedly or movably connected to a receiving device, wherein the measuring device 17 is integrated into the receiving device. It can also be provided that the receiving device is movably supported relative to the machine frame 5 and that acting on the receiving device

Abstützkräfte or Abstützmomente be measured. About a known geometry of the recording device can thus easily determine the reaction torque 21 of the motor 7.

The support of the motor 7 relative to the machine frame 5 can be realized in many ways. It is crucial for the present invention that a measured value is measured by means of the measuring device 18 or a plurality of measured values are measured from or from which the reaction torque 21 of the motor 7 can be determined via the geometry of the support arrangement.

Claims

claims

1. screwing machine (1) for tightening or loosening of

Rail fastening screws (9) with a rollable on a track (3)

Machine frame (5), with handles (8) for a displacement and with a motor (7) for acting on a screw head (11) with a torque (16) and with a device for torque limiting, characterized in that a measuring device (17) for Detecting a reaction torque (21) of the motor (7) relative to the machine frame (5) is arranged and that the motor (7) for limiting the torque (16) in dependence of the reaction torque (21) is driven.

2. screwing machine (1) according to claim 1, characterized in that the measuring device (15) comprises a force transducer for measuring a force acting on the motor (7).

3. screwing machine (1) according to claim 1 or 2, characterized in that the motor (7) is a hydraulic motor or an electric motor.

4. screwing machine (1) according to one of claims 1 to 3, characterized

characterized in that a controller (15) is provided, which is a for

Reaction torque (21) proportional measured value is supplied and that the controller (15) for controlling the motor (7) is set in dependence of the measured value.

5. screwing machine (1) according to one of claims 1 to 4, characterized

characterized in that the screw head (11) is rotationally connected to a drive shaft (10) of the motor (7).

6. screwing machine (1) according to one of claims 1 to 5, characterized

characterized in that the motor (7) on the machine frame (5) to a

predetermined axis is rotatably mounted.

7. screwing machine (1) according to claim 6, characterized in that the motor (7) about a shaft axis (20) of the motor (7) is rotatably mounted.

8. screwing machine (1) according to claim 6 or 7, characterized in that the motor (7) by means of a rolling bearing (19) on the machine frame (5) is mounted.

9. screwing machine (1) according to one of claims 6 to 8, characterized

in that the motor (7) is supported relative to the machine frame (5) by means of a torque support (18) and that the measuring device (17) is designed to detect a supporting force (22) applied by means of a torque support (17).

10. screwing machine (1) according to claim 9, characterized in that the measuring device (17) in the torque arm (18) is integrated.

1 . Screwing machine (1) according to one of claims 1 to 5, characterized

in that the motor (7) is attached to a receiving device of the

Machine frame (5) is fixed and that the measuring device (7) is integrated in particular in the receiving device.

12. A method for operating a screwing machine (1) according to one of

Claims 1 to 11, wherein the screw head (11) by means of the motor (7) with the torque (16) is acted upon, characterized in that by means of the measuring device (17) the reaction torque (21) of the motor (7) relative to the machine frame ( 5) is detected and that the motor (7) for limiting the torque (16) in dependence of the reaction torque (21) is driven.

13. The method according to claim 12, characterized in that for detecting the reaction torque (21) by means of a force transducer, a measured value for a force acting on the motor (7) force is measured, that the measured value of a controller (15) is supplied and that the controller (15) controls the motor (7) in dependence on the measured value.

14. The method according to claim 13, characterized in that the controller (15) an adjustable limit value is set and that the motor (7) is deactivated as soon as the measured value reaches the limit value.

15. The method according to claim 12 or 13, characterized in that the controller (15) a hydraulic pressure relief valve a

Limiting value dictates that a hydraulic motor until reaching the

Limit value is running, that the detected when stopping the hydraulic motor reaction torque is compared with a desired torque and that depending on this comparison, the controller (15) specifies an adjusted limit value.